Author Topic: Adding relays to the power window circuit  (Read 13011 times)

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Offline pinball

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Adding relays to the power window circuit
« on: April 25, 2008, 05:13:04 PM »
I would like to add relays to the power window circuit but Ive been unable to find any diagrams. 

There are 5 wires that connect to the power window switch, driver up and down, passenger up and down and a power feed wire.  If I cut the driver up wire, the bit that connects to the power window switch is now connectted to pin 86 on the relay and pin 85 is connectted to ground.  Then the other part of the driver up wire connects to pin 87 of the relay with a suitable power feed connectted to pin 30 of the relay. 

Is that correct?  Can I just run an extention wire from the power window power feed wire to pin 30 or does it need to be a seperate feed?

Does that make sense, if not let me know and I'll try and draw a circuit diagram
1979 Trans Am 403, imported directly into the UK, straight from the factory.

Ill-Eagle AC, Scotland

Offline lee01

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Re: Adding relays to the power window circuit
« Reply #1 on: April 25, 2008, 07:25:21 PM »
I made a little drawing with Paint of my own.
I,m almost ready to do mine.
*******NEW DIAGRAM    PLEASE CHECK LOWER*******
« Last Edit: April 27, 2008, 09:14:24 AM by lee01 »
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Offline 78ta

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Re: Adding relays to the power window circuit
« Reply #2 on: April 26, 2008, 04:26:41 AM »
Lee01,
That's a nice drawing but I think you want all of the 85's to be tied together and run to ground and all of the 87's to be tied together and run to your new 12v supply line. Not from the 85's to the 87's.

If you drew that up going by the excel spread sheet Russ made, I can see how you'd think the 85's should be tied to the 87"s as the red 12v line sort of starts and stops between the relays in his rendition but I'm pretty sure they are not.
 
The 85's are the ground for the relay coil. So when you push the window switch, that sends 12 volts to the 86. Current then runs through the actuating coil of the relay(86 to 85) to ground causing the relay to kick in.

The actual current flow for the motors is from 87(when the relay is actuated) to 30, through the motor to ground.

Randy

Offline 78ta

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Re: Adding relays to the power window circuit
« Reply #3 on: April 26, 2008, 05:07:28 AM »
Pinball,

Yes, wiring the relays the way you described should work. Russ's drawing had the 30 and 87 pins the opposite, meaning that the 12v supply went to the 87 and the output to the motor came from 30. I can't think of a reason why swapping the 87 and 30 connections would matter though.

I'm not sure which power window feed wire you're referring to. The one that goes to the switch from the existing PW relay or the one that goes _to_ the power window relay under the steering column.
Some one wrote that they found that they had a large voltage drop in the circuit breaker for the power window circuit. It's a metal box that plugs right into the fuse box. I would remove that circuit breaker and replace it with an inline fuse. I don't know what the terminals on the circuit breaker look like because I don't have power windows(yet) but I would think you'd be able to tap into the spot in the fuse box where the circuit breaker was for your new 12v source. 
If you wanted to leave the circuit breaker, you could do that and just run a new 12v line to the 87's directly. I'd put an inline fuse here though. The circuit breaker was self resetting and I haven't seen a current rating anywhere for it but it seems like I saw 25 amps for the power window circuit somewhere.
If/when you do add any new wire to the cicuit, you want to make sure it is at least 14 gauge wire. 12 gauge would be safer especially for the wires to the motors. Those are the ones that are carrying all the current. The ones going from the switch to the relays won't be carrying much at all now. 

By the way, if you've had any trouble with your power door locks, you can use the same relays to rewire those as well. The factory circuit is apparently wired such that the current has to go all the way from the driver's side switch through the passenger side switch and then to the lock motors and vice-versa. There's lots of plugs/connections along the way to get corroded and cause problems. IE....voltage drops which can cause weak lock/unlock. You can use these relays to rewire the circuit so that you have a good solid 12v's going directly to the motors from the relays instead of going across the car and back to the motors. I have a drawing (hand written=not pretty) if you'd like to see it. It requires two relays. 
« Last Edit: April 26, 2008, 05:19:10 AM by 78ta »
Randy

Offline pinball

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Re: Adding relays to the power window circuit
« Reply #4 on: April 26, 2008, 05:50:50 AM »
Hi lee01 and 78ta,

Thanks for replies.

78ta: I was thinking of just using the 12V feed wire that goes to the PW switch from the existing PW relay, instead off runing a new wire or would it be better to just run a new wire anyway?

My power locks have never worked, but while Im going to be doing some work on the electrics, I may as well have a look at the power locks, I would be interested in seeing your power lock drawing.
1979 Trans Am 403, imported directly into the UK, straight from the factory.

Ill-Eagle AC, Scotland

Offline lee01

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Re: Adding relays to the power window circuit
« Reply #5 on: April 26, 2008, 10:02:41 AM »
Lee01,
That's a nice drawing but I think you want all of the 85's to be tied together and run to ground and all of the 87's to be tied together and run to your new 12v supply line. Not from the 85's to the 87's.

If you drew that up going by the excel spread sheet Russ made, I can see how you'd think the 85's should be tied to the 87"s as the red 12v line sort of starts and stops between the relays in his rendition but I'm pretty sure they are not.
 
The 85's are the ground for the relay coil. So when you push the window switch, that sends 12 volts to the 86. Current then runs through the actuating coil of the relay(86 to 85) to ground causing the relay to kick in.

The actual current flow for the motors is from 87(when the relay is actuated) to 30, through the motor to ground.


Yes I kinda copy and make it simplier.
So I've made correction according to what you say.
Is this make more sense?
Current project:
90 Mustang GT 5.0
10 STI Sportech
Last T/A's
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Offline ta78w72

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Re: Adding relays to the power window circuit
« Reply #6 on: April 26, 2008, 10:18:41 AM »
78ta,  I think the schematic I did was correct, but I'm not a EE.  If a change needs to be made let me know and I'll change it...but I think lee01 had a hard time figuring out my poorly done schematic.  I can also see how he would think 87 tied to 85.  I'll try to make a change on it to make that more clear. 

The main thing is that we get a quality solution out to everyone.  No feelings are hurt if there is something wrong.  The best solutions come from a group of people providing input.  That's why I took the thread over at TAC about this and saved it and also tried to prepare a schematic.  Not only did I find a wiring error in the narrative, but all this information would have been lost when the TAC had the crash.  My main goal was to get something useful out to those who need it.

Lee01, once you get your wiring diagram figured out, we can use that one as the master that gets sent out to everyone if you don't mind.  Mine is very crude!

Lee01, 85 is ground and should have a black wire going to ground.  I had power coming in from the power source at terminal 87 and power from the switch at 86.  Power to the motor is out at 30.  Once 78ta sets us straight that these are correct...or gives us new routing, we're set.

Edit:
Lee01, in looking at the schematic I notice that you have two passenger downs coming from the switch.  Also, you should try to make the wire colors the same as the harness....that was my attempt.  That way, it  will be easy to modify the harness.  You did a good job on it though...it looks great and is easy to follow.
« Last Edit: April 26, 2008, 12:26:55 PM by ta78w72 »

Offline Aus78Formula

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Re: Adding relays to the power window circuit
« Reply #7 on: April 26, 2008, 12:19:59 PM »
I'd be interested in a diagram too. My car is in the electricians at the moment, been there for months actually. I tried to describe what I wanted done with extra relays etc but he didnt seem to understand, or else wasn't interested in doing the extra work!

Offline pinball

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Re: Adding relays to the power window circuit
« Reply #8 on: April 26, 2008, 12:54:09 PM »
hi lee01,

If I am understanding what 78ta is saying then all the 87 pins should be tied together to the 'new power from battery or fuse box' wire, all the 85 pins should be tied togethered and should be grounded.  In this particular situation pin 87a is not used, so can therefore be left unconnectted.

Thank you for your efforts in editing the diagram, as the other posters have said it would be great to get an actual diagram done, it seems to be such a popular problem, your diagram is going to help alot of people  ;)

I'll just be glad to be able to use my windows  ;D
1979 Trans Am 403, imported directly into the UK, straight from the factory.

Ill-Eagle AC, Scotland

Offline 78ta

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Re: Adding relays to the power window circuit
« Reply #9 on: April 26, 2008, 10:57:37 PM »
Wow, Lot going on here. I'm going to try and answer these one at a time.

Lee01,
Not exactly there yet...... :)

Maybe this will simplify it.
 
87's tied together and connected to new 12v source.
30's out to motors(2 up and 2 down).
85's tied together and run to ground.
86's, each one to a different control wire coming from the switch. Dr up, Dr Down, Pass up, Pass Down.
87A not used.

1. Change all of the red lines going to the 85's to black and attach a ground symbol to those wires.
2. Erase all the black lines going to the 87A's. 87A is not used in this case.
3. You already have the red line at the top left coming from the fuse box to the first 87. Just attach that red line to all the other 87's.

78taw72's suggestion to match the wires in the schematic to the actual wires is a good one. Here are the wire colors according to the chassis manual. I have an actual switch wire harness here so this is correct.
driver's side up - dark blue
driver's side down - brown
pass side up - dark blue w/white stripe (Good luck drawing that :) )
Pass side down - Tan (light brown)

Thank you for hanging in there. This is going to be a very nice and valuable schematic when you're done with it.
« Last Edit: April 27, 2008, 04:15:21 AM by 78ta »
Randy

Offline 78ta

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Re: Adding relays to the power window circuit
« Reply #10 on: April 26, 2008, 11:21:15 PM »
Pinball,

I wouldn't recommend using the pink wire for the feed to the motors(87's ).

As I said earlier, someone(I thought Russ 78TAW72) said that they found a 3 or 4 volt drop inside the circuit breaker for the power windows. This means that you could have a full 12v inside the fuse box but only 8 volts coming out of the circuit breaker. So if you use the pink wire, you'll be going through that circuit breaker and be taking a chance on having a low supply voltage which is the one of the original problems created by the factory design so your windows may still be slow. edit: I don't currently have power windows so I don't know how much trouble it would be to eliminate the circuit breaker as we've discussed. In a later post I mention just replacing it with a new one. I'm going to check on availability and price on them and post back. Looks like they're only about $9. I would think they originally lasted a few years before they went bad. Even if we replace the circuit breaker, we'll still tap on to the orange wire coming out of it (next to it on the fuse box)  and take that straight to the power feed (87) side of the relays.

You could try using the pink wire coming out of the original relay under the steering column to power the relay coils (86). In other words, leave all the wiring to the switch as is and use the 12v pink wire that goes to the switch to actuate the relays themselves. However, I don't know what the relay's minimum voltage threshold is for actuating. If you only give them 8 volts because of the loss through the circuit breaker, you could actually have a problem with the relays themselves working. This is not as likely to cause a problem with actuating the relays as it would be using that pink wire's voltage to actually power the motors themselves.

As far as the power feed to run the window motors(87), I would(and will) run a new 12 gauge 12v line from the fuse box, with a 25 amp inline fuse in it, straight to all of the 87's. Just tie all of the 87's together and connect them all to the one new 12v feed wire. 

Hope this helps. If not, let me know.

I'm typing a lot here so I'll be rereading these and editing as needed. Don't hesitate to question something that doesn't look right.

By the way, I'll try and get some sort of digital image of the door lock circuit I mentioned posted soon. I could post a pic of it but it has all of the wiring out to the switches etc and looks like chicken scratch on paper. I may try the paint method Lee01 used. That's looks great. Just not sure how tedious it would be for this circuit. Maybe I should turn it over to Lee01, the paint expert. It only requires two relays but man, there's wires everywhere because the switches are in the doors and the wires have to cross and tap into each other in several places. With the window circuit, each relay only does one job. With the door lock cicuit, the relays are tied together. 
« Last Edit: April 27, 2008, 04:42:50 AM by 78ta »
Randy

Offline 78ta

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Re: Adding relays to the power window circuit
« Reply #11 on: April 27, 2008, 03:10:07 AM »
Sorry this is so long and possibly jumps around some. I stopped several times to do research and kept adding more to it.

Ok 78TAW72,

The wiring diagram you did with excel was very creative, correct and useful to me but I knew where you were going with it and how it should work. I did not mean to criticize you at all. I was just saying, as you agreed in your last post, that I could see how Lee01 might have thought the 85's and 87's were tied together. That's a pretty complex drawing to fit in a small area using something like excel. I thought you did a great job with it.

The only thing I would add/change would be to inlcude replacing the circuit breaker with a 20 amp inline fuse since the circuit breaker, as I think you pointed out, was a source of some voltage loss/problems. That's easy enough to do on a drawing but I don't have power windows and therefore don't have the circuit breaker in my fuse box so I can't say how the circuit breaker physically plugs in and what type of connector you'd have to use to attach the new feed wire. I'm betting the circuit breaker just has two spade lugs. Does anyone know first hand how the PW circuit breaker plugs into the fuse box?  Can you simply plug a spade lug(flat male metal connector) into one of the holes left by the circuit breaker? edit:  I just looked at Hogheads PW page ( http://www.firebirdtransamparts.com/ ) and it looks like if you remove the circuit breaker, you'd have to hard wire across the terminals for it in the fuse box to bypass it. The main power feed(orange wire) plugs in just to the right of the circuit breaker. I'm wondering how much a new circuit breaker would be. That may be the simplest route. I just checked NAPA online and they have a spade terminal style 30 amp circuit breaker for $9. I'll go to the store and see if they actually have a PW circuit breaker for a firebird and post back. By the way, Hoghead's PW page states that the cicuit breaker is a 30 amp. I haven't seen any indication of it's rating anywhere in the manuals. 

I don't recall who wrote what regarding the wiring docs you sent me as they aren't signed. Someone mentioned in one of them that they used a car audio amplifier installation kit because it had a 50amp fuse in it. I'm looking at the power window circuit in the chassis manual and the fisher body manual. According to these schematics, GM used 12 and 14 gauge wire in this circuit. When considering the current capacity (ampacity) of a circuit, you have to base it on the smallest wire in the circuit(the weakest link). In this case, it is 14 gauge wire. I've looked at all of the wiring schematics in the chassis manual and it seems that GM used both 14 and 12 gauge wire in 20 and 25 amp circuits. So since the smallest wire in the circuit is 14 gauge, following GM's pattern regarding wire size and fuse size, the fuse required for the circuit could be a 20 or 25amp fuse. I've heard GM's wire ratings are very conservative so I've checked electroinics web sites and several state that 14 gauge stranded wire can carry up to 40 amps with 12v dc. Still, I would be concerned about using the factory 14 gauge wiring with a 50 amp fuse. If, for whatever reason, the circuit was pulling close to 50 amps, the 14 gauge wire will likely melt or worse before the 50 amp fuse blows.
If the person that was using the 50 amp fuse was also replacing EVERY wire in the circuit with 10 gauge wire, the wiring would be safe. The window motors supposedly have internal circuit breakers so they should be ok as well.

« Last Edit: April 27, 2008, 03:37:56 AM by 78ta »
Randy

Offline pinball

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Re: Adding relays to the power window circuit
« Reply #12 on: April 27, 2008, 04:50:00 AM »
Hi 78ta,

Thanks for the replies.  I hadnt picked up in your earlier post that there was such a voltage drop through the circuit breaker, is this labelled 'Existing Relay' in lee01 diagram?   I'll have to check what voltage drop I get across the circuit breaker in my car.  I guess the new 12V wire that is run from the fusebox or battery can be used to both power the relays and the motors, is that correct?  Im just trying to think of a way to do this using as much of the original wiring as possible.

Once again thank you for your help, it is really appreciated (I should say that goes for everyone that has replied :) )
1979 Trans Am 403, imported directly into the UK, straight from the factory.

Ill-Eagle AC, Scotland

Offline lee01

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Re: Adding relays to the power window circuit
« Reply #13 on: April 27, 2008, 08:56:16 AM »
*EDIT*  :P
« Last Edit: April 27, 2008, 09:15:09 AM by lee01 »
Current project:
90 Mustang GT 5.0
10 STI Sportech
Last T/A's
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Offline lee01

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Re: Adding relays to the power window circuit
« Reply #14 on: April 27, 2008, 09:12:17 AM »
Ok, this one I added the circuit breaker change to 20amp fuse.
I also delelted my other diagram to avoid mixed up
Current project:
90 Mustang GT 5.0
10 STI Sportech
Last T/A's
1979 x 4